In recent years, a pet toilet for treatment of excreta of a pet that is kept indoor has been designed, in which a pet toilet sheet that is able to absorb liquids is set on top of a pan-like tray that is placed on the floor surface, and a frame member is mounted on the tray to press down the toilet sheet (see Patent Literature 1, for example).
Such a pet toilet, however, has a layered structure composed of three layers: the tray, the toilet sheet and the frame member, and this necessarily increases the height of the toilet, particularly the height from the floor surface to the highest section of the frame member. Pets, and especially dogs, tend to dislike passing over frame members that are very high from the floor surface, and therefore may fail to enter onto the toilet sheet, often resulting in difficulty in excreting into the toilet.
In order to overcome problems caused by height, therefore, a pet toilet has been devised that is of the type described in Patent Literature 2, for example, in which the toilet sheet is spread directly onto the floor surface to eliminate the lowermost tray on which the toilet sheet is set. Such a pet toilet is generally constructed so that when the toilet sheet is directly spread onto the floor surface, such as flooring, portions of the toilet sheet are covered and pressed with the toilet sheet cover member. Such a construction is advantageous in that it is possible to reduce the height of the pet toilet by the amount of the eliminated tray, and to therefore reduce the height from the floor surface to the uppermost section of the cover member, so that the pet can pass over the cover member and enter the toilet sheet more easily.
However, because such a type of a pet toilet basically has the toilet sheet merely pressed down by the cover member, there has been one problem that when the pet steps its leg onto the cover member when it enters the toilet sheet, or when the pet enters onto the toilet sheet energetically, the cover member tends to shift on the toilet sheet and the location of the pet toilet on the floor surface also tends to shift.
Moreover, when the pet has excreted urine vigorously near the cover member, the urine can flow out of the toilet sheet through the gap between the bottom surface of the cover member and the top surface of the toilet sheet.